Guide for homeowners · Cost benchmark
Windows and doors cost in NI: 2026 price guide
By Conor Hamilton, Building & Renovation Contributor · 10 minute read
Published 7 June 2026 · Last reviewed 7 June 2026
Reviewed every quarter and updated whenever prices, platforms or recommendations change in the Northern Ireland market.
Edited by Mark Crawford, Digital Content Editor.
Replacing the windows and doors in a typical Northern Ireland three-bed semi runs roughly £6,000 to £10,000 supplied and fitted at mid-spec in 2026, with uPVC at the lower end and aluminium or triple glazing at the top. This guide breaks down the cost by tier, by individual unit, and covers the one big NI difference: there is no FENSA here, so windows go through council Building Control.
What replacement windows and doors cost in NI (2026)
Three tiers cover almost every whole-house job. These are turnkey figures, supplied and fitted with old units removed, for a typical three-bed semi with eight to ten windows.
| Tier | Typical spec | Whole house (2026) |
|---|
| Budget | uPVC, standard casements, 8 to 10 windows plus a back door | £3,000 to £6,000 |
| Mid-range | uPVC with A-rated glazing, plus a composite front door | £6,000 to £10,000 |
| Premium | Aluminium, flush-sash or triple-glazed, plus bifold or patio doors | £10,000 to £18,000+ |
Source: 2026 quotes from NI window installers cross-checked against published NI pricing (Hurricane Windows Belfast, Smart Homes NI) and Republic of Ireland comparison anchors (Expert Windows, BuildPro) converted from euro. NI fitting rates run roughly 10 to 20 per cent below the GB mainland.
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Cost per window and door
For a partial job, or to sanity-check a quote line by line, these are the NI 2026 supplied-and-fitted ranges per unit.
| Item | NI range (2026) | Note |
|---|
| uPVC casement window (small or medium) | £350 to £650 | Supplied and fitted |
| uPVC casement (large or bay) | £650 to £1,200 | Bay windows at the top end |
| uPVC back door | £550 to £900 | Standard half-glazed |
| Composite front door | £900 to £1,800 | Most popular front-door choice |
| uPVC French doors | £900 to £1,600 | Pair, supplied and fitted |
| Patio / sliding door | £1,200 to £2,500 | Two or three pane |
| Aluminium window (per unit) | £700 to £1,300 | Slimmer frames, dearer than uPVC |
| Aluminium bifold (3 pane) | £2,500 to £5,000 | Spec-driven, brand matters |
| Sash window (uPVC or timber) | £700 to £1,400 | Timber and conservation styles higher |
Source: NI installer quotes, June 2026. Ranges include removal of the old unit, fitting and basic making good, but not significant plaster or render repair, lintel work, or scaffolding for upper floors.
What drives the price
- Frame material. uPVC is the cheapest, aluminium the dearest (slimmer sightlines, around twice the price), with timber and timber-alternative in between. This is the single biggest lever.
- Glazing spec. A-rated double glazing is standard; triple glazing adds cost for marginal gains in most NI homes. Obscure, acoustic and toughened glass all add.
- Door choice. A composite front door costs roughly double a basic uPVC one, and bifold or patio doors are a tier above French doors.
- Size, style and quantity. Bay windows, sash styles and astragal bars cost more, and the more openings, the higher the total (though the per-unit rate often drops on a full-house order).
- Access and making good. Upper-floor windows may need scaffolding, and old or rendered openings can need lintel checks or plaster and render repair once the old frame is out.
Do you need FENSA in NI? No, and here is what you need instead
This is where Northern Ireland differs from every UK-wide guide. FENSA and Certass, the competent-person schemes installers use in England and Wales to self-certify window work, do not operate in NI. Replacement windows here are controlled work under NI Building Regulations, and approval comes from your local council Building Control, not from the installer ticking a self-certification box.
In practice that means the work should be notified to your council Building Control and meet the energy-efficiency standard, and you should keep the completion record, because a buyer’s solicitor will ask for evidence that replacement windows complied when you sell. We cover how this works in our NI Building Regulations guide. New windows also have to keep the required trickle ventilation, so do not let an installer block up vents to make a room feel less draughty.
Source: FENSA and Certass operate in England and Wales only; replacement windows in NI are approved through council Building Control under the Building Regulations (Northern Ireland) 2012, Technical Booklet F (conservation of fuel and power) and Technical Booklet K (ventilation).
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The costs people forget
- Making good. Plaster repair inside and render or sealant outside once old frames are out, more on older or pebble-dashed homes.
- Lintels and structural checks. An opening with a failed or missing lintel needs fixing before the new window goes in.
- Scaffolding or access. Upper-floor and dormer windows can add a few hundred pounds for safe access.
- Disposal. Removing and tipping old frames and glass, sometimes itemised separately.
- VAT at 20 per cent. Replacement windows are standard-rated; always check whether a quote includes it.
How to get reliable quotes
Window quotes are notoriously hard to compare because each company prices its own product. A few rules make them useful.
- Get three written quotes against the same schedule. List every window by room, size and style so each installer is pricing the same job.
- Be wary of high-pressure discounts. A price that is only valid if you sign today is a sales tactic, not a fair quote.
- Confirm Building Control. Ask how the installer handles the council Building Control notification, since there is no FENSA route in NI.
- Check the guarantee. Get the frame and glazing guarantee and any insurance-backed warranty in writing.
What to do next
Four steps before you sign anything.
1
Write a room-by-room window and door schedule so quotes are comparable.
2
Sanity-check quotes against the per-unit ranges above.
3
Confirm how the installer notifies council Building Control (no FENSA in NI).
4
Post the job free below and vetted NI installers will quote.
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Frequently asked questions
How much does it cost to replace all the windows in a house in NI in 2026?
For a typical Northern Ireland three-bed semi, a full set of replacement uPVC windows with a back door runs roughly £3,000 to £6,000 supplied and fitted, and £6,000 to £10,000 once you add A-rated glazing and a composite front door. Going to aluminium, flush-sash or triple glazing, or adding bifold or patio doors, pushes a whole-house job to £10,000 to £18,000 or more. The biggest single variables are the frame material (uPVC is cheapest, aluminium dearest), the number and size of windows, and whether any openings need structural work.
How much is a uPVC window supplied and fitted in NI?
A standard small-to-medium uPVC casement window costs about £350 to £650 supplied and fitted in NI in 2026, rising to £650 to £1,200 for a large or bay window. Aluminium windows run higher, around £700 to £1,300 each, for slimmer frames. These figures include removing the old window, fitting, and basic making good, but not significant plaster or render repairs around the opening.
How much does a composite front door cost in NI?
A composite front door is around £900 to £1,800 supplied and fitted in NI in 2026, which is why it is the most popular front-door upgrade: it sits between a basic uPVC door (about £550 to £900) and a timber or high-security door. The price depends on the door style, glazing, hardware and the locking system. A back door is usually cheaper than a front door of the same material.
Do I need a FENSA certificate for new windows in NI?
No, and this is where UK-wide guides get NI wrong. FENSA and Certass, the self-certification schemes installers use in England and Wales, do not operate in Northern Ireland. Replacement windows here are controlled work under NI Building Regulations and are approved by your local council Building Control, not self-certified by the installer. Make sure the work is notified to Building Control and keep the completion record, because a buyer’s solicitor will ask for evidence that replacement windows met the regulations when you come to sell.
Are new windows cheaper in NI than the rest of the UK?
Slightly. NI fitting rates run roughly 10 to 20 per cent below the GB mainland average, and prices sit close to the Republic of Ireland border counties once you convert from euro. The bigger swings come from the choices you make: frame material, glazing spec, and door styles move the price far more than your location does. Always get three written, like-for-like quotes against the same window schedule.
About the author
Conor HamiltonBuilding & Renovation Contributor · Newtownards, Northern Ireland
Conor writes the NI building and renovation cost benchmark guides for NI Trades. He draws on a civil-engineering background and on quotes from working FMB, OFTEC and NICEIC tradespeople across Northern Ireland to keep the price ranges realistic. He holds a BEng (Hons) in Civil Engineering from Queen’s University Belfast.
BEng (Hons) Civil Engineering, Queen’s University Belfast